Carbon Dioxide-Selective Membranes

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

Abstract Proposal Title:Carbon Dioxide-Selective Membranes, Proposal Number: CTS-0625758, Principal Investigator: Winston Ho, Institution: Ohio State University Abstract: The state-of-the-art process for the removal of carbon dioxide from gases, including synthesis gas for hydrogen and ammonia production and natural gas for its purification, uses aqueous amine solutions. The state-of-the-art process has certain draw backs and it therefore is important to develop an effective process with both capital and energy savings. The proposed research is aimed at a novel approach using a CO2-selective membranes. This novel approach combines the absorption and stripping of CO2, carried out in 2 separate steps in the commercial technology, into a one-step membrane process. This one-step process not only simplifies the separation process, but also eliminates the capital-intensive equipment of the commercial technology. This one-step process also overcomes the thermodynamic solubility limit of aqueous amine solutions. The specific objective of this proposal is to study the effect of steric hindrance, via incorporating sterically hindered amines in polymer membranes, on CO2 removal. This PI and his coworkers have shown that sterically hindered amines have much higher CO2 and H2S absorption capacities (about 60% higher) than unhindered amines. It is important to see if we can extend this significant steric effect from the aqueous amine solution to the solid polymeric membrane phase. This is the first of the kind of membranes capable of possessing high CO2 permeability and CO2/H2 selectivity at relatively high temperatures (100 180oC) needed for energy-efficient syngas purification. This proposed work not only is of a great scientific interest but also may provide improved membranes of significant technological importance. Potential broader impacts of the project are significant as this research is aimed at the novel CO2-selective membrane approach to overcome many deficiencies of the commercial gas treatment technology. This novel approach combines the absorption and stripping of CO2, carried out in 2 separate steps in the commercial technology, into a one-step membrane process. This one-step process not only simplifies the separation process, but also eliminates the needs for the absorber, the regenerator, two pumps for the loaded and regenerated amine solutions, and the pumping operations between the absorber and regenerator. This one-step process also overcomes the thermodynamic solubility limit of aqueous amine solution. Thus, this membrane approach will have both significant capital and energy savings. The membranes derived from this proposal have many potential applications including the purification of synthesis gas to produce high purity hydrogen for fuel cells, CO2 capture from flue gas for its sequestration, and CO2 removal from biogas, natural gas, confined space air, and ambient air.